This application relates generally to apparatus and method for venting fluid material from an enclosed space to atmosphere, and particularly to apparatus and method which are driven by solar energy for venting the enclosed space. The present invention has a particular utility for venting moisture from the interior of a built-up roofing system to the atmosphere.
In built-up roofing systems, in grain storage systems, and in numerous forms of existing housing-type structures which operate in moderately humid climates, moisture tends to be retained in substantially enclosed spaces within the housing. In a built-up roofing system, moisture can get into the interior of the system through the use of damp construction materials, through leaks in the roofing membrane or by migration of moisture from within the building. In air-conditioned buildings, conventional open-type vents often permit moisture to enter the system from the outside. Such moisture collects within the roofing system and is basically retained therewithin in a substantially enclosed condition by the normal roof membranes and insulation. Prior art structure for venting such moisture has consisted of open stacks extending from the interior of the roof system with the upper ends opening to atmosphere, and by apparatus such as shown in U.S. Pat. 2,600,947, 2,833,229 and 3,783,767.
Other forms of known solar powered devices are shown in U.S. Pat. Nos. 2,688,922, 2,601,905, 2,931,578, 3,436,908, 3,290,230, 3,168,450, 3,015,613, 2,820,744, 2,138,689 and 2,566,327.